Inhibitory effect of mucopolysaccharide polysulfate cream on hypertrophic scar formation in a rabbit ear model and its mechanisms of action / 中华皮肤科杂志

Objective:To investigate the inhibitory effect and mechanisms of action of mucopolysaccharide polysulfate cream on hypertrophic scar formation.Methods:Circular full-thickness wounds with a diameter of 6 mm were made in both ears of 16 New Zealand white rabbits to establish a rabbit ear model of hypertrophic scar. There were 3 hypertrophic scars in each rabbit ear. About 14 days after the operation, scars on the left ear were topically treated with mucopolysaccharide polysulfate cream, and served as the experimental group; scars on the right ear were topically treated with the cream vehicle, and served as vehicle control group. The dosage of topical agents for one rabbit ear was approximately 0.4 g, which were given twice a day for 6 consecutive weeks. Scar tissues were collected on days 0, 14 and 42, that is, 14, 28 and 56 after operation respectively, and subjected to hematoxylin and eosin (HE) staining, Masson staining and immunohistochemical study, so as to evaluate histopathological scores, measure the scar thickness and collagen fiber density, and determine the expression of type Ⅰ and Ⅲ collagen and the ratio of type Ⅰ/Ⅲ collagen. The t test and one-way analysis of variance were used to compare the indices between groups. Results:Compared with pretreatment histopathological manifestations, HE staining showed extensive extracellular matrix deposition, inflammatory cell infiltration and local hyperemia in the control group after 42-day treatment, but no obvious changes in the experimental group. The pathological scores of scar tissues on the rabbit ears significantly increased over time in the control group (days 0, 14 and 42: 4.16 ± 1.61, 6.50 ± 1.46, 6.53 ± 1.34, respectively; F = 13.69, P = 0.001) , while there was no significant change in the experimental group (days 0, 14 and 42: 4.65 ± 1.52, 5.13 ± 1.83, 5.38 ± 1.60, respectively; F = 0.78, P > 0.05) . Masson staining showed extremely high content of dark blue-dyed collagen fibers in the control group on day 42, but there was a decrease in the content of collagen fibers in the experimental group; with the increase in treatment duration, the thickness of scar tissues significantly increased in the control group compared with that before treatment ( F = 5.64, P = 0.007) , while there was no significant change in the experimental group ( F = 1.48, P > 0.05) . Immunohistochemical study revealed no significant change in the expression of type Ⅲ collagen in either the experimental group or the control group at any of the above posttreatment time points compared with that on day 0 ( F = 0.22, 0.92, respectively, both P > 0.05) , but the expression of type Ⅰ collagen and the ratio of type Ⅰ/Ⅲ collagen significantly increased in the control group ( F = 7.47, P < 0.001; F = 4.70, P = 0.005, respectively) . On day 42, the expression of type Ⅰ collagen and the ratio of type Ⅰ/Ⅲ collagen significantly decreased in the experimental group compared with the control group ( t = 3.04, P = 0.007; t = 2.35, P = 0.030, respectively) . Conclusion:Topical mucopolysaccharide polysulfate cream is effective in preventing and inhibiting scar hypertrophy by reducing the scar thickness and inhibiting the collagen fiber hyperplasia and type I collagen expression.

Evaluation of Collagen Fibers, MMP2, MMP9, 8-OHdG and Apoptosis in the Aorta of Ovariectomized LDL Knockout Mice Submitted to Aerobic Exercise / Avaliação de Fibras de Colágeno, MMP2, MMP9, 8-OH-Dg e Apoptose na Aorta de Ratas LDL Nocaute Ovariectomizadas Submetidas a Exercício Aeróbico

Abstract Background: In menopause, there is greater cellular exposure to oxidative stress, related to the decreased antioxidative effects of estrogen. These metabolic changes favor the progression of cardiovascular diseases, such as atherosclerosis. Abnormal function of the aorta - the most important artery - is associated with many cardiovascular diseases. Collagen, especially types I and III, is one of the most important aortic wall components and it can be affected by many factors, including menopause. The 8-OHdG is one of the main markers of DNA oxidative damage induced by reactive oxygen species (ROS). Objective: We aimed to investigate effects of moderate aerobic training on the ascending aorta of LDL-knockout (LDL-KO) and ovariectomized female mice. Methods: A total of 15 C57BL/6 mice and 15 LDL-KO mice were divided into experimental groups. The thickness and volume density of types I and III collagen fibers were performed by morphoquantitative analysis, whereas the MMP-2 and MMP-9 and 8-OHdG were detected by immunohistochemistry and apoptosis was detected by the TUNEL assay. The significance level for all tests was p < 0.05. Results: Exercise causes an increase in the thickness of the aorta in LDL-KO groups, particularly accentuated in the ovariectomized groups. The type I collagen fibers showed an increase in volume density influenced by training in both Control groups and in the LDL-KO group. Type III collagen density decreased in both groups. The MMP-2 showed moderade immunostaining in the tunica media in LDL-KO groups, which did not occur in the control groups and the MMP-9 stained irregularly in all tissues. The marker 8-OhdG was stronger in the exercise training groups. Additionally, the ovariectomy, the exercise training and the LDL-KO treatments increased apoptosis. Conclusion: These results suggest that moderate-intensity aerobic exercise in ovariectomized mice associated to an increase in LDL rate possibly increases oxidative stress and apoptosis induction.

Resumo Fundamento: Na menopausa, há maior exposição celular ao estresse oxidativo, relacionada à diminuição dos efeitos antioxidantes do estrogênio. Essas alterações metabólicas favorecem a progressão das doenças cardiovasculares, como a aterosclerose. A função anormal da aorta - a artéria mais importante - está associada a muitas doenças cardiovasculares. O colágeno, especialmente os tipos I e III, é um dos mais importantes componentes da parede da aorta e pode ser afetado por muitos fatores, incluindo a menopausa. Por sua vez, 8-OHdG é um dos principais marcadores de danos oxidativos do DNA induzidos por espécies reativas de oxigênio (EROS). Objetivo: Investigar os efeitos do treinamento aeróbico moderado na aorta ascendente de camundongos fêmeas, nocaute para LDL (LDL-KO) e ovariectomizadas. Métodos: Um total de 15 animais C57BL/6 e 15 animais LDL-KO foram divididos em grupos experimentais. A espessura e a densidade de volume das fibras de colágeno tipos I e III foram realizadas por análise morfoquantitativa; MMP-2 e MMP-9 e 8-OHdG foram detectadas por imunohistoquímica; e a apoptose foi detectada pelo ensaio TUNEL. O nível de significância adotado para todos os testes realizados foi p < 0,05. Resultados: o exercício causa aumento da espessura da aorta em grupos LDL-KO, particularmente acentuada em grupos ovariectomizados. As fibras de colágeno de tipo I mostraram aumento da densidade de volume influenciado pelo treinamento em animais controle e LDL-KO. A densidade do colágeno tipo III diminuiu em ambos os grupos. A MMP-2 mostrou imunomarcação moderada na túnica média em animais LDL-KO; em grupos controle, a MMP-9 marcou irregularmente em todos os tecidos. O marcador 8-OHdG foi mais forte nos grupos de treinamento de exercícios. Além disso, a ovariectomia, o treinamento físico e os tratamentos de LDL-KO aumentaram a apoptose. Conclusão: Esses resultados sugerem que exercícios aeróbicos de intensidade moderada em camundongos ovariectomizados associados ao aumento da taxa de LDL, possivelmente, aumentam o estresse oxidativo e a indução da apoptose.

Effects of fractional Er:YAG laser irradiation on collagen and elastic fibers in photoaged skin of Guinea pigs / 中华皮肤科杂志

Objective To evaluate the effect of fractional Er:YAG laser therapy on collagen and elastic fibers in photoaged skin of ultraviolet-irradiated Guinea pigs.Methods Sixty Guinea pigs were randomly divided into the non-intervention group (n =10) and model group (n =50) by a random number table.To establish a model of photoaging,the 50 Guinea pigs were irradiated by ultraviolet A (UVA) and ultraviolet B (UVB) on the back every other day for two months.Subsequently,the 50 mice were equally classified into five groups:photoaging group receiving no laser therapy,as well as 2-week,4-week,8-week and 12-week group receiving one,one,two and three sessions of successive multi-pulsed fractional Er:YAG laser therapy,respectively,on the left side (treatment side) of the back,with the right side as the control side.The interval of laser therapy was four weeks.Skin biopsies were obtained from the right and left side of the back of Guinea pigs after the laser therapy,and subjected to haematoxylin and eosin (HE) staining,Masson staining and Weigert-van Gieson staining.The content of hydroxyproline was measured by using an alkaline-hydrolysis method.Results The minimal erythema dose for UVA and UVB was 4224 mJ/cm2 and 504 mJ/cm2 respectively on Guinea pig skin.The model for photoaging was successfully established in 50 Guinea pigs after two months of irradiation with the cumulative dose of UVA and UVB being 459.36 J/cm2 and 54.81 J/cm2 respectively.HE staining revealed an obvious increase in newly-growing collagen and elastic fibers,which were arranged densely,in the treatment side compared with the control side of the back of Guinea pigs after laser therapy.The area ratio of collagen fibers stained positive for Masson's trichrome and content of hydroxyproline were significantly higher in the treatment side than in the control side of the 12-week group (0.70 ± 0.12 vs.0.63 ± 0.08,t =1.18,P ＜ 0.05;(4.73 ± 0.39) mg/g vs.(3.66 ± 0.85) mg/g,t =3.40,P ＜ 0.05).Conclusion Successive multi-pulsed fractional Er:YAG laser irradiation can result in an increase in collagen fibers and renewal of elastic fibers in superficial dermis of photoaged skin of Guinea pigs.

Morphological Changes in Disused and Denervated Old Rat Achilles Tendon Fibrils

BACKGROUND: This study tried to compare the morphological changes of collagen fibrils between disused and denervated old rat Achilles tendons with those of young rats through quantitative analyses of collagen fibril diameters by transmission electron microscopy (TEM). METHODS: Old (18 months old) and young (6 months old) male Sprague-Dawley rats were divided into 3 groups (n=8 in each group): a control group, a complete denervation group for 4 weeks after the transection of the right sciatic nerve, and a disuse group with hindlimb unweighing by tail suspension. Each explanted Achilles tendon was used for TEM observation. Under TEM, quantitative analyses of collagen fibril diameters were performed. RESULTS: All groups comprising old rats had smaller mean diameters and showed more left-shifted distribution of collagen fibril diameters than young rats. In particular, the disuse group of old rats showed a more prominent mean fibril diameter decrease than young rats. CONCLUSION: Disuse might cause a more prominent decrease of collagen fibril size in the old than the young.

The histological effects of early mobilization in the healing after achilles tendon of rabbits rupture repair / 中国医师杂志

Objective To offer the histological proof of rabbits rupture repair after early mobilization.Method New zealand rabbits were random divided into 3 groups, including normal group, mobilization group (the experimental group) , and immobilization group.All rabbits' achilles tendons were inspected, and the histological difference were observed under light microscope and electron microscope respectively.Result The collagen fibers of the achilles tendons in the mobilization group under light microscope showed that it arrayed more regularly than in immobilization group.Fibroblasts were more maturate.The diameters of collagen fibrils under electron microscope in mobilization group were thicker[(8.417 ± 1.649)μm vs (6.818 ± 1.025)μm, t = 2.76, P ＜ 0.05] than immobilization group.The results showed statistical significance[(26.915 ±2.123)nm vs (21.725 ±3.768)nm, t =4.12, P ＜0.01].Conclusion Early mobilization after operation can promote the histological healing of achiles tendon.

Effect of chronic fluorosis on myoardial collagen metabolism in rats / 吉林大学学报(医学版)

0. 05). Conclusion Chronic fluorosis has no obvious effect on myocardial collagen metabolism of rats and myocardial collagen is not likely the main target of fluoride.

Análise morfológica e bioquímica da sinóvia de coelhos imunizados com colágeno do tipo V / Morphological and biochemical analysis of the synovia of rabbits immunized with type V collagen

Descrevemos modelo original de sinovite experimental em coelhos imunizados com colágeno V com escasso processo inflamatório, intenso remodelamento matricial e vasculite. Analise morfológica e bioquímica foi realizada em coelhas Nova Zelândia (N=20) imunizadas com colágeno do tipo V, comparadas com controles. Foi observado o aumento dos colágenos I, III e V, oclusão do lúmen vascular e escasso processo inflamatório. A análise bioquímica confirmou a fibrose com aumento da síntese de colágeno. Nós postulamos que as alterações sinoviais descritas neste modelo foram conseqüência das particularidades do colágeno V, que promove manifestações imunológicas e clínicas semelhantes à esclerodermia.

We described an original model of experimental synovitis in rabbits immunized with collagen V with scant cellular infiltration, intense matrix remodeling and vasculitis. Morphological and biochemical analysis were realized in New Zealand female rabbits (N=20) immunization with type V collagen, compared with control rabbits. It was observed increase of collagen I, III and V, vascular lumen occlusion and scant inflammatory process. Biochemical analysis confirmed the fibrosis with increased synthesis of collagen. We postulate that synovial changes described in this model are consequence of collagen V particularities, which promotes immunologic and clinical manifestations similar to scleroderma.